Evaluation of in silico, in vitro α-amylase inhibition potential and antidiabetic activity of Pterospermum acerifolium bark.

Context: Pterospermum acerifolium (L.) Willd (Sterculiaceae) has been traditionally used in the treatment of diabetes mellitus but no scientific data has been published supporting the claimed ethnomedical use.
Objective: The present study was designed to estimate the in silico, in vitro α-amylase inhibition potential and anti-diabetic activity of Pterospermum acerifolium bark.
Materials and Methods: In silico studies were performed between human pancreatic α-amylase (HPA) and β-sitosterol by using autodock 4.2 software. In vitro α-amylase inhibition study was carried out with 50% ethanol extract of the bark (PABEE) and its various fractions. The active ethyl acetate fraction (PABEF) was sub-fractionated into three fractions (PABE1, PABE2 and PABE3). Two doses (15 and 30 mg/kg) based on acute toxicity studies, of the above fractions were subjected to antidiabetic screening in vivo by STZ-nicotinamide induced type II diabetic rats.
Results: In silico studies showed the potent inhibition of β-sitosterol on human pancreatic amylase (HPA) with an estimated inhibition constant (Ki) of 269.35 nmol and two hydrogen bond interactions. PABEF showed marked α-amylase inhibition (69.94%) compared to other fractions. Diabetic rats treated with PABE3 (30 mg/kg) reduced the levels of fasting blood glucose, HbA1c, ALT, AST, ALP, triglycerides, total cholesterol, TBARS significantly (p < 0.01) and increased the levels of HDL-C, catalase, GSH, SOD significantly (p < 0.01) as compared to that of diabetic control animals. Histological studies on PABE3 treated group showed remarkable positive changes in β-cells.
Conclusion: The present study confirmed the antihyperglycemic activity along with its status on hepatic biomarkers, antihyperlipidemic and antioxidant properties of Pterospermum acerifolium bark.